The present invention relates generally to cellular materials used in structural applications and specifically to materials comprising hierarchical cellular lattices and related methods of using and manufacturing the same.
Sandwich panels are structural materials that may comprise a core enclosed between two sheets of material. Some of the existing lattice structure geometries used in sandwich panel cores include tetrahedral, pyramidal, and octet truss, kagome, and honeycomb. Typically, lattice structures utilizing trusses to form the core material of a sandwich panel are constructed from a lattice with a single unit cell size, that is, the trusses comprising the lattice are all of equal size. The size of the cells can of course be varied from one lattice to another, but typically in a given lattice, the cells are all of one size.
An embodiment of a sandwich panel core or the like that may be comprised of a lattice structure utilizing a network of hierarchical trusses, synergistically arranged, to provide support and other functionalities disclosed herein. Since this design results in a generally hollow core, the resulting structure maintains a low weight while providing high specific stiffness and strength. Sandwich panels are used in a variety of applications including sea, land, and air transportation, ballistics, blast and impact impulse mitigation, thermal transfer, multifunctional structures, armors, ballistics, load bearing, construction materials, and containers, to name a few. Any of the front, bottom or side panels involved may be an adjacent structure, component or system or may be integral with an adjacent structure, component or system. It should be appreciated that the panels (face sheets) may be applied to the sides, rather than only top and bottom. Adjacent structures may be, for example, floors, walls, substrates, platforms, frames, housings, casings, or infrastructure. Adjacent structures may be associated with, for example: land, air, water vehicles and crafts; weapons; armor; or electronic devices and housings.
An aspect of an embodiment (or partial embodiment) comprises a structure. The structure may comprise a first lattice structure, the first lattice structure comprising: a first primary array, wherein the first primary array comprises an array of first order cells; and at least one of the first order cells comprising second order cells; an ancillary array, wherein the ancillary array comprises an array of second order cells; and at least one of the second order cells comprising third order cells; and wherein the ancillary array is nested with the first primary array, whereby the second order cells of the ancillary array are essentially coaligned with: the second order cells of the first primary array, the first order cells of the first primary array, or both the second order cells of the first primary array and the first order cells of the first primary array. An aspect of an embodiment (or partial embodiment) further comprises a second lattice structure, the second lattice structure comprising: a second primary array, wherein the second primary array comprises an array of first order cells; and wherein the second primary array is mated with the first primary array to form a third lattice structure, whereby at least one of the first order cells of the first primary array are oppositely oriented to and essentially coaligned with at least one of the first order cells of the second primary array.
An aspect of an embodiment (or partial embodiment) comprises a structure. The structure may comprise a first lattice structure, the first lattice structure comprising: a first primary array, wherein the first primary array comprises an array of first order cells; and an ancillary array, wherein the ancillary array comprises an array of second order cells; and wherein the ancillary array is nested with the first primary array, whereby the second order cells of the ancillary array are essentially coaligned with the first order cells of the first primary array. An aspect of an embodiment (or partial embodiment) further comprises a second lattice structure, the second lattice structure comprising a second primary array, wherein the second primary array comprises an array of first order cells; and wherein the second primary array is mated with the first primary array to form a third lattice structure, whereby at least one of the first order cells of the first primary array are oppositely oriented to and essentially coaligned with at least one of the first order cells of the second primary array.
An aspect of an embodiment (or partial embodiment) comprises a method of making a structure, the method comprising forming a first lattice structure through the steps comprising: providing a first primary array, wherein the first primary array comprises an array of first order cells; and at least one of the first order cells comprising second order cells; providing an ancillary array, wherein the ancillary array comprises an array of second order cells; and at least one of the second order cells comprising third order cells; and nesting the ancillary array with the first primary array, whereby the second order cells of the ancillary array are essentially coaligned with: the second order cells of the first primary array, the first order cells of the first primary array, or both the second order cells of the first primary array and the first order cells of the first primary array. An aspect of an embodiment (or partial embodiment) further comprises providing a second lattice structure, the method comprising: providing a second primary array, wherein the second primary array comprises an array of first order cells; and mating the second primary array with the first primary array to form a third lattice structure, whereby at least one of the first order cells of the first primary array are oppositely oriented to and essentially coaligned with at least one of the first order cells of the second primary array.
An aspect of an embodiment (or partial embodiment) comprises a method of making a structure, the method comprising forming a first lattice structure through the steps comprising: providing a first primary array, wherein the first primary array comprises an array of first order cells; and providing an ancillary array, wherein the ancillary array comprises an array of second order cells; and nesting the ancillary array with the first primary array, whereby the second order cells of the ancillary array are essentially coaligned with the first order cells of the first primary array. An aspect of an embodiment (or partial embodiment) further comprises a providing a second lattice structure, the method comprising: providing a second primary array, wherein the second primary array comprises an array of first order cells; and mating the second primary array with the first primary array to form a third lattice structure, whereby at least one of the first order cells of the first primary array are oppositely oriented to and essentially coaligned with at least one of the first order cells of the second primary array.
It should be appreciated that any number of arrays may be stacked, nested and mated on top of another. It should be appreciated that any number of the top, bottom, and side panels (facesheets) may be implemented by being attached or in communication with any of the arrays (and layers, stacking, mating and nesting of arrays). Further, it should be appreciated that any number of the top, bottom, and side panels (facesheets) may be implemented by being disposed between any of the arrays (and layers, stacking, mating and nesting of the arrays).
These and other objects, along with advantages and features of the invention disclosed herein, will be made more apparent from the description, drawings and claims that follow.
The foregoing and other objects, features and advantages of the present invention, as well as the invention itself, will be more fully understood from the following description of preferred embodiments, when read together with the accompanying drawings, in which:
The present disclosure sets forth a hierarchical lattice structure that comprises unit cells of various sizes connected together to form a lightweight lattice structure with improved specific stiffness and strength.
It should be appreciated that the cross sectional shapes of the ligaments may also be varied in order to change the overall structural properties of the lattice structure, as well as for other desired or required purposes. Possible cross sectional shapes for the ligaments include, but are not limited thereto the following: circular, triangular, rectangular, square, oval and hexagonal (or any combination or variation as desired or required).
It should be appreciated that the ligaments may be hollow, semi-solid, or solid, or any combination thereof.
In
Unit cells of other embodiments of the present disclosure may comprise more or less than three second order cells. For example, if unit cell 100 included a fourth ligament such that the shape of the unit cell was pyramidal, such a unit cell could also be comprised of four second order pyramidal cells, where each second order cell would utilize a portion of a ligament of the first order cell as one of its ligaments.
Although
The materials for manufacturing these unit cells encompass any material subject to deformation, punch and die, casting, injection molding, or other forming methods: these include, but are not limited to, metals, metal alloys, inorganic polymers, organic polymers, ceramics, glasses, and all composite derivatives, or any combination thereof. In some embodiments, the material used to construct cells of one order may be different than the material used to construct cells of another order. In some embodiments, different cells of the same order may be comprised of different materials. Similarly, as will be discussed later, panels implemented with the core may be of the same or different materials as the core.
Nesting may be accomplished when a portion of a ligament of a higher order cell of a primary array abuts a ligament of a lower order cell of an ancillary array along at least a substantial portion of the length of the ligament of the lower order cell. Nesting may also occur when a ligament of a cell from an ancillary array abuts along at least a substantial portion of the length of a ligament of a similarly ordered cell of a primary array. When either or both of these nesting scenarios occur, the respective cells are said to be nested and “co-aligned” with each other. When at least one cell from a primary array is nested with at least one cell from an ancillary array, the arrays are said to be nested with each other. In an embodiment, when two arrays are nested, at least one ligament of each of the highest ordered cells in the ancillary array will abut to a portion of a ligament of one of the highest ordered cells in the primary array. As an example, in referring to
In
By way of example and not limitation, the lattice structures provided herein are illustrated as comprising unit cells replicated in two dimensions. In other embodiments, although not shown, the unit cells making up a lattice structure may also be formed in three dimensions, thus creating a three dimensional cube-shaped array or lattice structure. In other embodiments, the unit cells making up a lattice structure could be replicated solely in one dimension.
It should be appreciated that any one of the primary arrays, nested arrays, or mated arrays or lattice structures, or combinations thereof may be implemented as the core of a sandwich panel or other structure that the core or panel may be in communication with. The panels and/or cores may be implemented with or as part of floors, columns, beams, walls, jet or rocket nozzles, land, air or water vehicles/ships, armor, etc.
It should be appreciated that any face sheets (or any desired or required components or structures) may be attached to the core (or in communication with the core or other structure or components) by any suitable means, including but not limited to brazing, transient liquid phase bonding, welding, diffusion bonding, or adhesive bonding after construction (or any other available adhesion process). In some embodiments, if the materials are constructed of a polymer they are attached together by an adhesive. In some embodiments, if the materials are constructed of a metal, they are attached through welding or brazing.
By way of example and not limitation, the lattice structures and arrays shown in the figures of the present disclosure as resting on a flat surface. In some embodiments a lattice structure or array may be curved, such that it does not rest on a flat surface. For example, a lattice structure might take the shape of an arc or be used to form the shell of a cylinder. Thus, since in some embodiments the lattice structure may be curved, any face sheet applied to such an embodiment will also be curved. In some embodiments, the lattice structure might be used to form a rocket or jet fuel nozzle. For example, the core or lattice (with or without panels) may be circular or at least semi-circular to provide an opening or nozzle for a jet or rocket. Similar designs may be implemented to provide a conduit or structure for any medium transfer there through. This application of the lattice structure is facilitated by the structure's high strength and thermal conductivity.
The core or lattice (with or without panels) may be implemented for walls or floors for housings, compartments, buildings, floors, vehicles, or infrastructure.
The lattice structures described above have many applications including use as the cores of sandwich panel structures. Utilizing embodiments of the present disclosure, sandwich panels with ultra-light and high specific stiffness and strength lattice cores can be designed to outperform competing load supporting structures made with honeycomb or other conventional cores. These sandwich panels may be used in minimum weight structural applications, including many forms of mechanized transportation. Embodiments of the present disclosure can also be used to construct materials with improved impact or blast load mitigation. For example, these materials can sustain larger compressive forces along their struts before truss buckling occurs and they can suffer larger face sheet deformations before face sheet tearing is initiated. Embodiments of the present disclosure also enable materials with superior cross flow heat exchange, since the hollow structure allows coupling of a fluid coolant driven between the struts to heat transported through the struts by conduction. The hollow structure also enables the placement of other elements within the core. Embodiments of the present disclosure may also be used to create armors that have high ballistic resistance, in other words the strength of the structure increases the force needed to crush the material. Embodiments of the present disclosure may also be used to create armors, storage or buildings that mitigate blast impact.
An embodiment of this present disclosure can be designed to control the collapse of the first order cells during an impact with a rigid object, making it a preferred material system for impact or blast energy absorption. The increased surface area of a structure with a multiplicity of cell sizes can also be used as a support system for catalysts where the large cell size regions provide easy transport of reactants and products of the reaction enhanced at the catalytically coated surfaces of the trusses. When cells are arranged in this way, a high surface energy is enabled upon which other materials can be added for a wide range of applications. For example, an embodiment of the present disclosure could be used for the deposition of thin film batteries resulting in a load supporting, easily cooled structure with a very high energy storage density.
In some embodiments of the present disclosure, arrays of unit cells (unit cell arrays) can be fabricated from thermoformable materials through the use of an injection molding process.
In certain embodiments, the polymer 502 may be polypropylene, but alternative embodiments may use any other suitable thermoplastic polymer capable of being heated into a liquid state and then cooled to a solid state. By way of example and not limitation, polystyrene and polyethylene could also be used. One skilled in the art will recognize that in other embodiments, many different methods for injecting liquid into a mold could be used. Other embodiments may use any suitable injection apparatus to propel two or more polymers into a mold to form a unit cell in a process known as reaction injection molding. Still other embodiments may use any suitable injection apparatus to propel liquid metal into a mold to form a unit cell in a process known as metal injection molding. Still other embodiments may use any suitable injection apparatus to inject ceramic materials mixed with thermoplastic binders into a mold to form a unit cell in a process known as ceramic injection molding.
A cell array 602 formed by an injection molding process may be used in various applications to provide support in structural materials. A cell array 602 formed by an injection molding process may also be used as a template in further processing, as shown in
If a hollow truss structure is desired, the inner material of the coated carbonized unit cell array 702 can be removed by the process of burnout, by which the coated carbonized unit cell array 702 is subjected to a temperature that exceeds the melting point of the inner material of the coated carbonized unit cell array 702 but not the deposited material, thus leaving the deposited material in tact in the same shape as the original unit cell array 602. While the preceding example involves a carbonized polymeric unit cell array used as a template for deposition, other embodiments may utilize unit cell arrays made from other types of materials, including but not limited to metals, metal alloys, inorganic polymers, organic polymers, ceramics, glasses, and all composite derivatives, or any combination thereof.
A person skilled in the art would recognize that the lattice structures described in the present disclosure could be manufactured in other ways including lattice block construction, constructed metal lattice, and metal textile lay-up techniques.
It should be appreciated that various aspects of embodiments of the present method, system, devices, article of manufacture, and compositions may be implemented with the following methods, systems, devices, article of manufacture, and compositions disclosed in the following U.S. patent applications, U.S. patents, and PCT International patent applications and are hereby incorporated by reference herein and co-owned with the assignee:
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International Application No. PCT/US2008/073377 entitled “Synergistically-Layered Armor Systems and Methods for Producing Layers Thereof,” filed Aug. 15, 2008.
International Application No. PCT/US2008/060637 entitled “Heat-Managing Composite Structures,” filed Apr. 17, 2008.
International Application No. PCT/US2007/022733 entitled “Manufacture of Lattice Truss Structures from Monolithic Materials,” filed Oct. 26, 2007.
International Application No. PCT/US2007/012268 entitled “Method and Apparatus for Jet Blast Deflection,” filed May 23, 2007.
International Application No. PCT/US04/04608, entitled “Methods for Manufacture of Multilayered Multifunctional Truss Structures and Related Structures There from,” filed Feb. 17, 2004, and corresponding U.S. application Ser. No. 10/545,042, entitled “Methods for Manufacture of Multilayered Multifunctional Truss Structures and Related Structures There from,” filed Aug. 11, 2005.
International Application No. PCT/US03/27606, entitled “Method for Manufacture of Truss Core Sandwich Structures and Related Structures Thereof,” filed Sep. 3, 2003, and corresponding U.S. application Ser. No. 10/526,296, entitled “Method for Manufacture of Truss Core Sandwich Structures and Related Structures Thereof,” filed Mar. 1, 2005.
International Patent Application Serial No. PCT/US03/27605, entitled “Blast and Ballistic Protection Systems and Methods of Making Same,” filed Sep. 3, 2003.
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International Application No. PCT/US03/16844, entitled “Method for Manufacture of Periodic Cellular Structure and Resulting Periodic Cellular Structure,” filed May 29, 2003, and corresponding U.S. application Ser. No. 10/515,572, entitled “Method for Manufacture of Periodic Cellular Structure and Resulting Periodic Cellular Structure,” filed Nov. 23, 2004.
International Application No. PCT/US02/17942, entitled “Multifunctional Periodic Cellular Solids and the Method of Making Thereof,” filed Jun. 6, 2002, and corresponding U.S. application Ser. No. 10/479,833, entitled “Multifunctional Periodic Cellular Solids and the Method of Making Thereof,” filed Dec. 5, 2003.
International Application No. PCT/US01/25158 entitled “Multifunctional Battery and Method of Making the Same,” filed Aug. 10, 2001, U.S. Pat. No. 7,211,348 issued May 1, 2007 and corresponding U.S. application Ser. No. 11/788,958, entitled “Multifunctional Battery and Method of Making the Same,” filed Apr. 23, 2007.
International Application No. PCT/US01/22266, entitled “Method and Apparatus For Heat Exchange Using Hollow Foams and Interconnected Networks and Method of Making the Same,” filed Jul. 16, 2001, U.S. Pat. No. 7,401,643 issued Jul. 22, 2008 entitled “Heat Exchange Foam,” and corresponding U.S. application Ser. No. 11/928,161, “Method and Apparatus For Heat Exchange Using Hollow Foams and Interconnected Networks and Method of Making the Same,” filed Oct. 30, 2007.
International Application No. PCT/US01/17363, entitled “Multifunctional Periodic Cellular Solids and the Method of Making Thereof,” filed May 29, 2001, and corresponding U.S. application Ser. No. 10/296,728, entitled “Multifunctional Periodic Cellular Solids and the Method of Making Thereof,” filed Nov. 25, 2002.
It should be appreciated that various aspects of embodiments of the present method, system, devices, article of manufacture, and compositions may be implemented with the following methods, systems, devices, article of manufacture, and compositions disclosed in the following U.S. patent applications, U.S. patents, and PCT International patent applications, and scientific articles, and are hereby incorporated by reference herein:
Of course it should be understood that a wide range of changes and modifications could be made to the preferred and alternate embodiments described above. It is therefore intended that the foregoing detailed description be understood that it is the following claims, including all equivalents, which are intended to define the scope of this invention.
In summary, while the present invention has been described with respect to specific embodiments, many modifications, variations, alterations, substitutions, and equivalents will be apparent to those skilled in the art. The present invention is not to be limited in scope by the specific embodiment described herein. Indeed, various modifications of the present invention, in addition to those described herein, will be apparent to those of skill in the art from the foregoing description and accompanying drawings. Accordingly, the invention is to be considered as limited only by the spirit and scope of the following claims, including all modifications and equivalents.
Still other embodiments will become readily apparent to those skilled in this art from reading the above-recited detailed description and drawings of certain exemplary embodiments. It should be understood that numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of this application. For example, regardless of the content of any portion (e.g., title, field, background, summary, abstract, drawing figure, etc.) of this application, unless clearly specified to the contrary, there is no requirement for the inclusion in any claim herein or of any application claiming priority hereto of any particular described or illustrated activity or element, any particular sequence of such activities, or any particular interrelationship of such elements. Moreover, any activity can be repeated, any activity can be performed by multiple entities, and/or any element can be duplicated. Further, any activity or element can be excluded, the sequence of activities can vary, and/or the interrelationship of elements can vary. Unless clearly specified to the contrary, there is no requirement for any particular described or illustrated activity or element, any particular sequence or such activities, any particular size, speed, material, dimension or frequency, or any particularly interrelationship of such elements. Accordingly, the descriptions and drawings are to be regarded as illustrative in nature, and not as restrictive. Moreover, when any number or range is described herein, unless clearly stated otherwise, that number or range is approximate. When any range is described herein, unless clearly stated otherwise, that range includes all values therein and all sub ranges therein. Any information in any material (e.g., a United States/foreign patent, United States/foreign patent application, book, article, etc.) that has been incorporated by reference herein, is only incorporated by reference to the extent that no conflict exists between such information and the other statements and drawings set forth herein. In the event of such conflict, including a conflict that would render invalid any claim herein or seeking priority hereto, then any such conflicting information in such incorporated by reference material is specifically not incorporated by reference herein.
This application claims benefit under 35 U.S.C. 119(e) from U.S. Provisional Application Ser. No. 61/038,227, filed on Mar. 20, 2008, entitled “Cellular Lattice Structures with Multiplicity of Cell Sizes and Related Method of Use,” the entire disclosure of which is hereby incorporated by reference in its entirety.
This invention was made with United States Government support under Grant No. N00014-07-1-0114, awarded by the Defense Advanced Research Projects Agency/Office of Naval Research. The United States Government has certain rights in the invention.
Number | Date | Country | |
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61038227 | Mar 2008 | US |